Self-Assembly In Situ Selenization Engineering to Synthesize High-Performance Ag2Se Thin Films

Ag2Se thin film devices have attracted significant interest in energy harvesting technologies for powering microscale systems. In this work, an in situ selenide diffusion strategy is employed to prepare Ag2Se thin films, optimizing the carrier transport by tuning in situ synthesis temperature. The optimized carrier mobility of ∼871.43 cm–2 V–1 s–1 is achieved, leading to a high room-temperature electric conductivity of ∼1235 S cm–1. Correspondingly, a decent Seebeck coefficient (|S| > 120 μV K–1) is obtained due to the optimal carrier concentration of approximately 1 × 1019 cm–3. Consequently, the Ag2Se film synthesized at 423 K exhibits a high power factor of ∼20.54 μW cm–1 K–2 at room temperature. A thermoelectric generator with 5 single legs is assembled by Ag2Se thin films. This device is capable of generating an output voltage of approximately 8.58 mV and a corresponding power of approximately 3.76 nW when subjected to a temperature difference of 40 K. The study presents an effective method for enhancing the thermoelectric performance of Ag2Se thin films.